1. Preheat oven to 180C / 350F / Gas 4. Grease two 18 cm/7 in round sandwich cake tins and line the base of each with non-stick baking paper. Select a small saucepan and a heatproof bowl that will fit over it. Place the chocolate and the milk in the bowl. Bring a small saucepan of water to just blow simmering point. Place the bowl…